Seal arrangement for filter element; filter element assembly; and, methods

ABSTRACT

A filter element arrangement is provided which includes a media pack comprising Z-filter media, a preform and an overmold sealing a portion of the interface between the preform and the media pack, and also forming an air cleaner seal for the filter element. The overmold preferably comprises molded, foamed, polyurethane. A variety of media pack shapes can be used.

CROSS-REFERENCE TO RELATED APPLICATION

The present application includes, with some edits and additionalinformation, the disclosure of U.S. provisional application 60/532,783filed Dec. 22, 2003. A priority right is claimed to that provisionalapplication, to the extent appropriate. The complete disclosure of U.S.provisional application 60/532,783 is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to air cleaners with removable andreplaceable, i.e., serviceable, filter element or cartridge components.Although other applications are possible, the invention described isparticularly useful in air cleaners for use in filtering intake air forengines (used for example in: vehicles, construction, agricultural andmining equipment; and, generator systems). The invention specificallyconcerns seal arrangements provided on serviceable filter elements orcartridges, for such air cleaners. The invention also concerns methodsof assembly and use.

BACKGROUND

Air streams carry contaminant material therein. In many instances, it isdesired to filter some or all of the contaminant material from the airstream. For example, air flow streams to engines for motorized vehiclesor for power generation equipment, construction equipment or otherequipment, gas streams to gas turbine systems and air streams to variouscombustion furnaces, carry particulate contaminant therein. It ispreferred for such systems that the selected contaminant material beremoved from (or have its level reduced in) the air or gas. A variety ofair filter arrangements have been developed for contaminant reduction.In general, however, continued improvements are sought.

SUMMARY

According to the present disclosure a filter element or cartridge isprovided, for use in air filtering. In general the filter element orcartridge comprises a media pack including opposite inlet and outletends. The media pack defines: a set of inlet flutes open at the inletend of the media pack to passage of air to be filtered therein, theinlet flutes being closed preferably at a location within a distance of10% of the total length of the inlet flutes from the outlet end of themedia pack; and, a set of outlet flutes closed to passage of air to befiltered therein preferably at a distance within 10% of the total lengthof the inlet flutes from the inlet end of the media pack and open thepassage of filtered air therefrom at the outlet end of the media pack.The element or cartridge further includes: a preform positioned adjacenta first one of the inlet and outlet ends of the media pack; and, anovermold formed of seal material having a first portion sealing at ajoint or interface between the preform and a first end of the media packat which the preform is positioned; and, a second portion oriented toform an air cleaner seal, between the filter element (or cartridge) andan air cleaner, when the filter element is installed for use. The firstand second portions of the overmold are integral with one another, in apreferred, convenient, arrangement.

In certain preferred applications, the media pack is a coiled z-filtermedia arrangement; and, the overmold comprises foamed polyurethane. Themedia pack can have a variety of shapes and configurations. Two examplesdepicted are: an oval shape, for example having a racetrack perimeter orcross-sectional shape; and, a circular perimeter or cross-sectionalshape. A variety of alternate shapes, are possible.

The combination of the preform and the overmold, form a preferred sealarrangement for a filter element. Methods of preparation and use arealso provided. Also, arrangements for use are generally described.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of a filter element according to afirst embodiment of the present disclosure.

FIG. 2 is a top view of the filter element component of FIG. 1.

FIG. 3 is a cross-sectional view taken along line 3-3, FIG. 2.

FIG. 4 is an enlarged fragmentary view of a portion of FIG. 3.

FIG. 5 is an enlarged, perspective view of a component used in thefilter element of FIG. 1.

FIG. 6 is a cross-sectional view of the component of FIG. 5, taken alongline 6-6 thereof.

FIG. 7 is a side elevational view of a filter element according to asecond embodiment of the present disclosure.

FIG. 8 is a top view of the element shown in FIG. 7.

FIG. 9 is a cross-sectional view of the arrangement depicted in FIG. 8,taken along line 9-9 thereof.

FIG. 10 is an enlarged, fragmentary, view of a portion of FIG. 9.

FIG. 11 is a fragmentary schematic, cross-sectional view of a moldarrangement useable to form a seal component of the arrangement depictedin either FIG. 1 or FIG. 7.

FIG. 12 is a schematic cross-sectional view of the mold of FIG. 11,depicted with a pool of non-cured polymeric seal material therein.

FIG. 13 is a view of the mold of FIG. 12 with certain pre-formed filterelement componentry positioned therein.

FIG. 14 is a view of FIG. 13 with a media component positioned therein.

FIG. 15 is a view of FIG. 14, with the seal material foamed andsubstantially cured.

FIG. 16 is a view of preform and media pack component in a moldaccording to the process of FIGS. 11-15.

FIG. 17 is an optional end piece useable in the component of FIG. 1.

FIG. 18 is a cross-sectional view of the optional piece of FIG. 1.

FIG. 19 is a fragmentary, schematic, perspective view of z-filter mediauseable in arrangements according to the present disclosure.

FIG. 20 is a schematic, cross-sectional view of a portion of the mediadepicted in FIG. 19.

FIG. 21 is a schematic view of examples of various corrugated mediadefinitions.

FIG. 22 is a schematic view of a process for manufacturing media useableaccording to the present disclosure.

FIG. 23 is a schematic cross-sectional view and optional end dart formedia flutes useable in arrangements according to the presentdisclosure.

FIG. 24 is a schematic perspective view, analogous to FIG. 19, of amedia material useable in the filter elements of FIG. 1 and FIG. 7,shown with a flow direction opposite to.

FIG. 25 is a schematic view of a system using an air cleaner having afilter cartridge component according to the present disclosure.

FIG. 26 is a fragmentary, cross-sectional view showing a plug in acentral core of the filter cartridge of FIG. 9.

DETAILED DESCRIPTION I. General Information

The present disclosure relates to filter elements (sometimes calledcartridges) useable in air cleaner assemblies. In general, the preferredfilter elements of concern herein are those in which: (a) the media ofthe elements comprises a first corrugated sheet of media attached to asecond sheet of media (typically a flat media or nearly flat media) toform a single facer; and (b) in which the single facer combination iseither wound or stacked, to create a media arrangement comprising aplurality of inlet flutes open at an inlet end face of the filter mediaand closed at or near (typically within 10% of the total length of theinlet flutes of) the outlet face of the media; and, a plurality ofoutlet flow flutes seal closed at or near the inlet face of the media(i.e., typically within 10% of the total length of the outlet flutes ofthe inlet face), and open at the outlet end face of the media. Suchmedia arrangements are well known and are described for example in U.S.Pat. Nos. 5,820,646; 5,772,883; 5,902,364; 5,792,247; 6,190,432 and6,350,291, the complete disclosures of these six U.S. patents beingincorporated herein by reference. Herein, such media will sometimes bereferred to as z-filter media; and, media packs formed from such mediaas z-filter media packs. A characteristic of such media packs, and theones described herein is that they are closed to passage of unfilteredair through the packs, between the opposite end faces.

Many variations of such media can be used, with the principles accordingto the present disclosure. For example, the end seals of the flutes(flute seals) can be provided in a variety of ways, including throughutilization of sealant beads; darting, folding or other arrangements fordistorting the shape of the flute at the end and/or closing and sealingthe flute ends; and through combinations thereof. Not all flutes need tobe sealed closed in the same way. The particular approach to sealing isgenerally a matter of choice, not specifically related to the generalprinciples described herein (except as indicated below) in connectionwith provision of seals between the serviceable filter element and ahousing or housing component, in use.

Another variable is the specific shape of the flutes. Tapered flutes inaccord with PCT Application No. WO 97/40918 and PCT Publication NumberWO 03/47722 and other flute shapes can be used, with arrangementsaccording to the principles disclosed. Of course, straight (non-tapered)flutes can, and often will, be used.

Another variable with respect to the media arrangement, is whether themedia is configured in a “coiled” arrangement or a “stacked”arrangement. The principles described herein will typically be appliedin connection with “coiled” arrangements, for reasons which will beapparent from the following discussions. However, certain of theprinciples could be applied in connection with arrangements that arestacked.

Herein the term “coiled” and variants thereof, when used to refer to amedia pack form from z-filter media, is meant to refer to a media packformed by coiling a single combination strip of media or single facer,made from a strip of corrugated media secured to flat or nearly flatsheet (the combination being a single facer), in order to form the mediapack. Such coiled media can be made in a variety of shapes including:round or cylindrical; oval, for example racetrack; square; orrectangular with rounded corners; and, they can even be configured inconical or similar arrangements. Examples of selected ones of these aredescribed in U.S. Pat. No. 6,350,291 and U.S. provisional applicationSer. No. 60/467,521, filed May 2, 2003, the complete disclosures ofwhich are incorporated herein by reference.

Herein the term “stacked arrangements” and variants thereof generallyrefers to media packs that are not formed from a single combinationstrip of media that is coiled, but rather to media packs formed from aplurality of strips of media or single facer (corrugated media securedto flat or nearly flat media); the strips being secured to one anotherin a stack or block form. Stacked arrangements are described for examplein U.S. Pat. No. 5,820,646, at FIG. 3, incorporated herein by reference.

In general, z-filter media pack arrangements as described, are used inserviceable filter elements (or cartridges), i.e., filter elements (orcartridges) that are removable and replaceable with respect to an aircleaner in which they are used. Generally, such z-filter media packs areprovided with sealing arrangements for engagement with portions of aircleaner parts such as a housing, in use. Herein, such seals are referredto as “air cleaner seals” or “housing seals,” or by variants thereof. Avariety of such air cleaner seals are known. One type, involving anoutside or outwardly directed radial seal, is described in U.S. Pat. No.6,350,291 at Ref. #250, FIG. 5.

Other types of seals useable with z-pack media are axial pinch seals, asdescribed for example in U.S. Pat. Nos. 6,348,085; 6,368,374 and U.S.Publication U.S. 2002/0185007 A1, incorporated herein by reference; and,internally directed radial seals, as described for example in U.S.Provisional 60/457,255 filed Mar. 25, 2003 at FIG. 12, the completedisclosure of which is incorporated herein by reference.

In general z-pack media and its preparation are characterized in moredetail herein below, in Section VII.

II. An Example Element, FIGS. 1-6.

The reference numeral 1, FIG. 1, generally depicts a serviceable filterelement (sometimes called a cartridge) according to the presentdisclosure. The filter element 1 depicted, comprises a z-filter mediapack 2 having an air cleaner seal arrangement 3 positioned thereon.

Again, herein, the term “air cleaner seal arrangement” and variantsthereof is generally meant to reference a seal arrangement 3 provided ona serviceable filter element 1 in such a manner that, when the filterelement 1 is installed in an air cleaner for use, the seal arrangement 3provides for an air seal with appropriate componentry or portions of aircleaner, typically an air cleaner housing. The term “serviceableelement” in this context, is meant to refer to a filter element 1 whichis removable and replaceable with respect to other portions of an aircleaner.

The particular air cleaner seal arrangement 3 depicted comprises anoutside radial seal member. By the term “outside radial seal member” inthis context, it is meant that the surface 6 which forms a seal with anair cleaner component, in use, is directed radially outwardly, ratherthan radially inwardly with respect to the portion of the serviceablefilter element 1 on which it is mounted. The principles described hereincould be applied with alternate orientations and types of seals, but theparticular seal configuration characterized is a convenient,advantageous, example.

In general, during operation, air flow through the z-filter media pack 2is shown by inlet arrow 9 and exit arrow 10. It is a characteristic ofz-filter media packs, that air flow therethrough is generally such thatthe inlet flow arrow and exit flow arrow are generally parallel to oneanother. That is, the only turns the air needs to make in passagethrough the element 1 are minor turns in flow through media pack 2,since the air flow flutes are generally parallel to one another, andparallel to the direction of inlet and outlet flow. It is noted that anopposite direction of air flow to that shown by arrows 9 and 10 ispossible, but this particular direction of air flow shown, in use, isadvantageous. When constructed and oriented for use in this manner, themedia pack 2 has an inlet end or flow face 15 and an opposite exit endor flow face 16.

For the example shown, the inlet flow face 15 and exit flow face 16 areeach substantially planar and are substantially parallel with oneanother. Although alternate arrangements are possible, the principlesdisclosed herein are particularly well considered for this application.

FIG. 2 is a top plan view of filter element arrangement 1. Referring toFIG. 2, the z-filter media 2 and seal arrangement 3 are provided with anoval outside perimeter shape, in this instance corresponding to twosimilar, opposite, curved ends 20, 21 spaced apart by two opposite,generally straight, sides, 22, 23. Herein this specific ovalconfiguration will generally be referred to as a “racetrack” shape.Racetrack shaped z-filter media pack elements are described in the priorart, for example, in U.S. Pat. No. 6,350,291 at FIG. 10. It will be seenthat many of the principles of the present disclosure can be applied inelements having media packs with alternate peripheral shapes, forexample circular, as described herein below. Another variation in theoval shape would one in which the opposite sides are not straight, butare curved somewhat, with less curvature than the ends. Another shapewhich is possible, is a shape which has two pairs of opposite, generallystraight, sides which may or may not have a slight curvature to them,with four substantially curved corners. An example of this type ofelement is described in U.S. provisional application 60/457,255, in FIG.22, the complete disclosure of which is incorporated herein byreference.

The various shapes identified in the previous paragraph, indicate thatthe principles herein can be applied to a wide variety of coiled shapes,not just the ones shown in the figures.

Referring to FIG. 1, the filter element 1 includes an optional end pieceor skid skirt 30 thereon, at an opposite end of the media 2 from theseal arrangement 3. The optional end piece or skid skirt 30 can be usedto provide engagement between element 1, and structure in a housing,during use, to facilitate installation. Examples of such end pieces areshown and described, in PCT Publication number WO 03/095068, publishedNov. 20, 2003, at FIGS. 4 and 8, the complete disclosure of PCTpublication WO 03/095068 being incorporated herein by reference. Theoptional end piece 30 is discussed again below, in section V inassociation with description of FIGS. 17 and 18.

Referring to FIG. 2, seal arrangement 3 comprises: a rigid preform partor insert 35; and, a molded seal component 36. By the term “preformpart” and variants thereof, as used in this context herein, it is meantthat part 35 is formed prior to formation of the molded seal component36 to form the seal arrangement 3. Indeed, in a typical manufacturingprocess for filter element 1, as described below: media pack 2 would bepreformed; part 35 would be preformed; and, the two parts (2, 35) wouldbe placed together in a mold, for formation of the molded seal component36. Herein, the molded seal component 36 is sometimes referred to as an“overmold,” or by variants thereof. Among other things, as will beunderstood from the following descriptions, the term “overmold” in thiscontext indicates that the molded seal component 36 is molded in placeon the media pack 2 and preform 35, and is not itself preformed.

Attention is now directed to FIG. 3. FIG. 3 is a cross-sectional viewtaken along line 3-3, FIG. 2. The cross-section of FIG. 3 is through theshorter or narrower dimension of the element 1, FIG. 1. However, similarfeatures will be viewable, if the cross-section were taken along thelonger axis, i.e., line Y-Y, FIG. 2.

The media pack 2, FIG. 3, is a coiled media pack. In general the mediapack 2 comprises a corrugated media sheet secured to a facing sheet,often a flat or nearly flat sheet, to form a strip or single facer,which is itself coiled in the configuration shown. Thus, the media pack2 comprises a single strip of the corrugated sheet facing (typicallyflat or non-corrugated) sheet, or single facer, coiled and configured asshown. In FIG. 2, although the media pack 2 is shown schematically, theouter three coils are indicated. Referring to FIG. 1, the outside tailend of the outer most coil is shown at 37. For the embodiment shown,tail end 37 is sealed and secured in position, by a hot melt sealantstrip 38, although alternatives are possible.

Referring again to FIG. 3, it is noted that there is no center board,center gap, center piece or center seal schematically shown in the mediapack 2. The media pack 2 is simply shown schematically with respect tothis point. Center boards can be used, for example as described in U.S.Pat. No. 6,348,084, incorporated herein by reference. Interdigitatedcenter strips can be used, for example as described in U.S. ProvisionalApplication Ser. No. 60/467,521, filed May 2, 2003. Center seals canalso be used, for example as described in U.S. Provisional ApplicationSer. No. 60/467,521, filed May 2, 2003. No specific choice from amongthese, and variants, is meant to be indicated with respect to FIG. 3.However, as is apparent from a review of the figures and furtherdescription herein, a center of the media pack 2 would be sealed closed,in some manner, to prevent the flow of unfiltered air between the twoopposite end faces 15, 16; i.e., so unfiltered are cannot flow outwardlyfrom an end face.

Referring to FIG. 3, the preform part 35 depicted includes threesections generally comprising: housing seal support section 40; mediaengagement periphery or skirt 41; and, media face cross piecearrangement 43.

Attention is directed now to FIG. 4. FIG. 4 is a fragmentary enlargedview of a portion of FIG. 3. In FIG. 4 it can be seen that no portion ofpreform 35 extends around the outer periphery or side 2 a of the mediapack 2. This will be preferred, for arrangements according to thepresent disclosure, although alternates are possible. For the particulararrangement depicted in FIG. 3, media engagement portion 41 includes anedge 45 which is brought into engagement with flow face 16 of thez-filter media pack 2 and which for the example shown does not projectto, or beyond, an outer perimeter edge 16 a of flow face 16, althoughalternatives are possible. The particular preform 35 depicted includes asmall ridge 45 a, FIG. 6 which projects slightly into media pack 2.Preferably ridge 45 a is no greater than 1 mm and comes to a fine point,to help contain flow of rising urethane, during formation of theovermold 36, and desirably from extending across flow face 16.

As described above in reference to FIG. 3, it is noted that theparticular z-filter media pack 2 depicted comprises a coiled mediaarrangement. In FIG. 4, the outer three coils 46 a, 46 b and 46 c areformed. The ends of coils 46 a, 46 b and 46 c, adjacent surface 16, areshown comprising ends folded or darted closed at 47. Such folding ordarting is described, for example, in U.S. Provisional Application Ser.No. 60/467,521, filed May 2, 2003, incorporated herein by reference.

Referring still to FIG. 4, molded seal component 36 is positioned with aportion 48 overlapping and sealing a joint 49 where preform part 35engages flow surface 16 of the media pack 2. Preferably the molded sealcomponent 36 includes a portion 51 which extends beyond the joint 49 ina direction away from flow face 16 (toward opposite flow face 15, FIG.3) a distance of at least 5 mm, preferably at least 8 mm, and typicallya distance within the range of about 9 mm to 18 mm, inclusive.

In general, portions 48 and 51 of the molded seal component 36, providethen, for a sealing between the media pack 2 and the preform part 35 atthis location, and also for sealing around and against media pack 2,adjacent face 16, to inhibit undesired, contaminated, air flow at thisregion. Typically, if the media pack does not include a covering orcoating of some type, portions 48 and 51 will contact the single facersheet of the media directly. In other cases, material on the media packwill be between the media and portions 48 and 51. In both instances,portions 48 and 51 engage the media pack 2.

Referring to FIG. 1, and in particular to hot melt seal strip 38,preferably the strip 38 is continuous and terminates, underneath region51 of overmold 36, at a location spaced at least 4 mm from face 16, FIG.4. Typically an extension of 6-12 mm of strip 38 will be positionedunderneath overmold 36. The termination of strip 38 at least 4 mm fromsurface 16 ensures that over a distance of at least 4 mm, the sealmaterial of overmold 36 is sealed directly to the media pack 2 adjacentend face 16. This will help avoid leak between the overmold 36 and themedia pack 2 at this location.

Referring to FIG. 4, molded seal component or overmold 36 furtherincludes air cleaner seal portion 54. Air cleaner seal portion 54includes a radial outer surface 56, configured in a preferred manner,for sealing with an air cleaner component. The particular surface 56 isdepicted, as a stepped surface portion 56 a having a shape similar tothe shape of the seal surface portion at reference 250 depicted in U.S.Pat. No. 6,350,291 at FIG. 7, the complete disclosure of which isincorporated herein by reference.

From review of FIG. 3, it can be seen that portion 40 of preform part 35is positioned to back up housing seal 56 and stepped portion 56 a ofmolded seal composition or overmold 36. Thus, preform part 35, in part,serves a function of providing for rigid backup to the strength of theseal when air cleaner seal portion 54 is compressed in the thickness(preferably at least 10% in thickness at the portion of mostcompression) upon installation in an air cleaner, with compression beingof surface 56 toward portion 40. Preferably, the distance of compressionis within the range of 1.5-2.8 mm, at the thickest part 56 b of seal 56,more preferably about 1.9-2.5 mm. As can be seen from a review of FIG.3, portion 40 is positioned to operate as a backup to the seal, becauseit projects outwardly (axially) from one of the flow faces 15, 16.

The recess of surface 40 across face 16, from outer periphery 2 a of themedia pack 2, provides that the filter element 1 can be installed in aircleaners that are originally configured, for example, to receiveelements such as element 450, FIG. 15 of U.S. Pat. No. 6,350,291,incorporated herein by reference. Of course alternate configurations arepossible. Of course surface 40 is preferably positioned so the supportedhousing seal 56 projects at or outwardly from the outer perimeter of themedia pack, in preferred arrangements.

Media engagement portion 41 is configured to extend radially outwardly,in extension between portion 40 and edge 57. Media engagement portion 41is configured as a radially outwardly directed skirt, from region 40.This outward extension means that ends of outlet flutes in the z-filtermedia pack 2, at region 60, FIG. 3, are not closed to passage of airtherefrom, during filtering operation. If region 41 was not positionedas a flared, diagonal, skirt, but rather section 40 extended to point61, flutes in region 60 would be blocked by extension 41, for air flowtherefrom. This would lead to increased restriction, and less efficientuse of the media. Preferably angle X, FIG. 6, is within the range of20°-70°, to accommodate the desired skirt. The angle X is the anglebetween the inside surface of skirt 41 and the media face 16.

Referring to FIG. 4, it is noted that for the particular arrangementshown skirt 41 is sized and positioned to leave region 64 in face 16(corresponding to the otherwise open ends of exit flutes in an outerflute wrap 46 a in the media pack 2), exposed to receive a portion ofmolded seal component 36 therein, as indicated at 66. This can providefor advantage. In particular, this allows some of overmold 36 to riseinto the media pack 2, as described below, during molding.

It is noted that for the preferred element 1 depicted in FIG. 4, noportion of the molded seal component 36 is positioned along interiorsurface 40 a of section 40. Further, preferably no portion of moldedseal component 36 is provided along inner surface 41 a of region 41,except possibly for some bleed or flash immediately adjacent edge 45.This latter prevents undesired levels of flash across surface 16 andprovides for a convenient manufacture. Section 40 could be configured,and overmold 36 formed, to allow sealant in region 40 a, but this wouldnot be preferred.

Still referring to FIG. 4, media face cross piece arrangement 43 extendsacross media face 16, in engagement with region 41 of preformed part 35.Media face cross piece arrangement 43 prevents the media pack 2 fromtelescoping, in the direction of arrow 10, FIG. 1, during use.

A variety of cross piece configurations are useable. In FIG. 2, theparticular cross piece arrangement 43 depicted, comprises: a grid ofparallel extensions 43 a between opposite sides 22, 23; interconnectedby diagonal framework 43 b.

In FIG. 5, a perspective view is provided, showing preformed part 35. Itcan be seen that the preform part 35 can be formed as a single integralunit, for example through injection molding or other molding processes.It is preferably formed from a polymer such as a (33% for example) glassfilled nylon material.

Referring again to FIG. 4, molded overmold or seal component 36 includesa portion 70 overlapping part of end 71 of preform part 35. This is anartifact from a preferred molding operation, as described below.

Referring to FIG. 4, it is noted that where cross-brace 43 engages skirt41, the angle of the skirt 41 relative to the face 16 may be interruptedsomewhat. However, in general, at other locations the skirt 41 will havea preferred angle X as characterized above.

It will be understood that the techniques described herein can beapplied in a wide variety of element configurations and sizes. Thefollowing dimensions are provided as examples only, and to helpunderstand the wide application of the present techniques. The overmold36, in its thickest location, could be about 10-12 mm thick, for exampleabout 11.5 mm. The longest cross-sectional dimension of the racetrackshaped media pack could be about 300-320 mm, for example about 308 mm.The shortest cross-sectional dimension of the racetrack shaped elementcould about 115-125 mm, for example about 121 mm. The length of thestraight sides could be about 175-195 mm, for example about 188 mm.

Before formation of arrangements such as described above is discussed,and certain advantages relating to the configuration are described,application of the principles in an alternate configuration will bediscussed in connection with FIGS. 7-10.

III. The Arrangement of FIGS. 7-10

Attention is first directed to FIG. 7. FIG. 7 is a side elevational viewof a serviceable filter element (or cartridge) 101. The filter element101 comprises a z-filter media pack 102 and seal arrangement 103. Theelement 101 further includes optional end piece 104 at an end 102 b ofmedia pack 102 opposite from an end 102 a in which seal arrangement 103is located.

The media pack 102 comprises a coiled single facer having first andsecond, opposite, flow faces 105, 105 a. It would, of course, have anoutside tail end, not shown, which would be secured down, for example,with a sealant strip analogous to strip 38 above.

In general, and referring to FIG. 7, surface 106 of seal arrangement103, is configured to provide a seal, as an outwardly directed radialseal, with a housing or air cleaner component in use (of coursealternatives are possible). Surface 106 may be configured, incross-section, analogously to surface 56, FIG. 4.

Attention is now directed to FIG. 8, in which element 101 is depicted intop plan view. From the view of FIG. 7, it can be seen that element 101is a generally circular outer perimeter 108 defined by both the outercircumference of the seal arrangement 103 and media pack 102. In FIG. 8,grid work 109 is viewable, extending across flow face 105; in thisinstance face 105 preferably being an outlet flow face.

Attention is now directed to FIG. 9, which shows a cross-sectional viewthrough element 101. From FIG. 9, it can be seen that the sealarrangement 103 comprises a preformed part 110 and an overmold or moldedseal component 111. The preform part 110 and molded seal component 111may generally be analogous to the preform part 35 and molded sealcomponent 36 of the embodiment shown in FIGS. 1-5, except made round.

Specifically, element 101 includes a core 113, around which the mediapack 102 is wound. Core 113 can be provided in snap fit engagement witha portion 114 of preform part 110. A variety of engagement arrangementscan be used, including the one, for example, described at FIG. 5 in U.S.Pat. No. 6,517,598, incorporated herein by reference. Core 113 is shownin schematic. It would typically be provided with a plug therein. Theplug could be integral with a remainder of core 113 or be added thereto.The plug or other closure in core 113 would generally operate to preventflow between faces 105 a, 105 which is not filtered.

In FIG. 10, an enlarged fragmentary view of a portion of FIG. 9 isshown. The preform part 110 includes a housing seal support 116; and, amedia pack engagement portion 117, configured as a radially outwardlydirected skirt 118; and media face cross piece arrangement 109 (FIG. 8).(At region 114 the inside outward skirt 118 is shown filled because thecross-section is taken through cross piece grid work 109, FIG. 8.) Forelement 101, these components generally provide the same basic operationas the analogous components for element 1, FIG. 1.

IV. Process for Assembly of Elements According to FIGS. 1-10.

In general, elements corresponding to element 1, FIG. 1, and element101, FIG. 6, are formed the processes involving the following:

-   -   1. Preforming the media pack component (2, 102).    -   2. Preforming the preformed part (35, 110) of the seal        arrangement.    -   3. Positioning the preform part (35, 110) and media pack        component (2, 102) appropriately with respect to one another in        a mold.    -   4. Overmolding a seal material to form the appropriate molded        seal component of the arrangement.    -   5. Demolding.    -   6. Optionally placing the skid (30, 104) on an end of the        element opposite the seal.

In this context, the term “overmolding” and variants thereof are meantto refer to molding a molded seal component 36, 111 in position: (a)with a portion of the molded seal component 36 over the outside of jointbetween the preformed part (35, 110) of the seal arrangement and themedia pack (2, 102); and, (b) with a portion of the same seal component36, 111 (i.e. preferably a portion integral with a remainder of theovermold) positioned to form an air cleaner seal. Typical and preferredprocesses will use, for the formation of the molded seal component, afoaming polyurethane, as described below. Herein, a molded sealcomponent 36 which has been made by overmolding as defined, willsometimes be referred to as an overmold. The portions of the overmoldseal, are preferably integral with one another; the overmold 36, 111being preferably molded from a single pool of polymer.

Typically and preferably, the thickness of the molded seal component, inthe region of the seal surface, is configured so that compression of thethickness of the thickest portion of the molded seal component in thisregion, will be at least 10%, and typically at least 15%, when theelement (1, 101) is installed in an air cleaner for use. This can beaccomplished with configurations as shown, using materials as describedbelow.

A typical process is described herein, in connection with FIGS. 11-16.

Attention is first directed to FIG. 11. In FIG. 11, reference numeral180 identifies a mold arrangement useable to form the overmold sealarrangement of the present disclosure. Mold arrangement 180 is shown infragmentary, cross-section. The portions indicated will provide anunderstanding of how the overmold seal arrangement can be formed. Theremainder of the mold will be configured either round or obround, etc.,depending on the particular instance of application.

Referring to FIG. 11, the particular mold arrangement 180 depicted is amulti-part mold 181. That is, the mold 180 includes more than one piecefit together, to form the mold in which the overmolding process occurs.The particular multi-part mold 180 depicted comprises three parts 183,184 and 185 that are fit together, to form the mold. Aperture 189, whichextends through three parts 183, 184, 185 when they are appropriatelyaligned, FIG. 11, can be used to receive a pin or similar member tosecure the mold together.

In general, part 183 forms the basic mold structure including: an innerreservoir portion 192, in which uncured resin is placed, for the moldingprocess; inner wall 193, against which a preformed part would be placedin use; shelf 194 on which an edge of the preform part would rest,during the molding process; central wall 195 and shelf 196 whichsupports additional mold parts as described; and, outer wall 197, whichprovides an outer support structure to the assembly 180.

The second part 184 comprises a mold insert having an extension 200 witha surface 201 that forms a portion of the outer surface of the moldedpart of the seal arrangement in use. In this instance surface 201includes a portion 202 which, in combination with central wall 195provides a mold undercut 203 molding a particular portion of the sealingsurface of the resulting seal portion, as discussed below in connectionwith FIG. 15. Part 184 further includes upper extension 205 which restson shoulder 196.

Finally, part 185 includes inner wall 215 and upper flange 218. Theflange 218 extends over portion 205 of center part 184. Inner wall 215includes a surface 216 which will define selected portions of the sealmember, during the molding process, as discussed below in connectionwith FIG. 15. Section 217 will cap the mold, and engage media, during apreferred molding operation.

Attention is now directed to FIG. 12, in which assembly 180 is depictedwith curable material 225 positioned within reservoir 192 up to fillline 226. The material 225 would generally comprise resin which, duringa cure process, will foam and rise as a cure to form the moldable sealcomponent. Typically, during molding and use the material 225 willexpand in volume at least 80%, a preferred material increasing about100%, in volume.

In FIG. 13, the mold assembly 180 having resin 225 therein is shownhaving preformed part 230 therein. The preform part 230 couldcorrespond, for example, to preform part 35, FIG. 1. It could alsocorrespond to preform part 110, FIG. 7. However if used with thearrangement of FIG. 7, in some instances it would already be attached tothe media pack.

Attention is now directed to FIG. 14 in which the mold arrangement 180is depicted with preform part 230 and media pack 231 positionedappropriately. It is noted that an outer surface 232 of media pack 231is sized to engage portion 217 of the mold part 185.

Attention is now directed to FIG. 15. In FIG. 15 the material at 235 ismeant to indicate the foamed, risen, substantially cured resin; i.e.,the overmold (corresponding to overmold 36, FIG. 1, or overmold 103,FIG. 7). By the term “substantially cured” it is meant that the resin iscured sufficiently to have reached a shape which will generally bemaintained, as it further cures. From FIG. 15, some of the followingimportant features relating to the molding operation can be understood:

-   -   1. At region 240, the most outwardly projecting portion of the        molded seal member 235 (number that above) is formed. Portion        240 then, will form the outer most portion of the outwardly        directed radial seal member, i.e., the part that compresses most        in use as an air cleaner seal;    -   2. Surface 241 is a portion of mold undercut, which is used to        form a portion of region 240.    -   3. At region 245, rise of the material 235 around the outside        surface 232 of the media pack 231 is capped or stopped by mold        piece 185, in particular by region 216 of mold piece 185.

At location 247, some of the resin of overmold 235 has risen into themedia pack between an outer most layer 248 of the media pack 231 and thelayer underneath. This rise will tend to close off any otherwise openflutes at this location. In general, this will render the outer mostlayer of the media pack (for example layer 46 a, FIG. 4) such that whileit can be used for filtering material, air must pass into the next innerlayer, before it can exit the media pack. What this means or ensures isthat even if the outer most wrap of media pack is damaged duringhandling or installation, leakage will not result. Thus, in a preferredarrangement, a third set of flutes, closed at both ends, is present inthe media pack. This third set is present, preferably, only in theoutermost wrap. These flutes would otherwise be outlet flutes, and willsometimes be referred to by such terms.

For the process shown in FIGS. 11-16, the media pack is one which hasclosed ends at the inlet flutes, adjacent the outlet flow face, dartedclosed, to provide the edges viewable. Alternates of course arepossible, including ones that are not darted at all. The overmoldmaterial is shown risen up into the open ends of the outlet flutes, atthe outlet face of the media, in the region indicated at 247.

Along regions 249, 250, the resin material 236 completely lines an outersurface of preform 230, securing it in place. At region 255, material235 is positioned over a part of an end 256 of preform 230.

In the particular arrangement shown, FIG. 15, the overmold 235 is asingle integral member, molded from the resin 225, FIG. 14.

Demolding can be accomplished by forcing the element out of the mold180, in a powered process. Equipment to cause the forcing can engage thecross pieces on the preform 230. Generally the overmold 235 willcompress sufficiently, to be pushed past undercuts in the mold. It isanticipated that typically, with materials and configurations describedherein, demolding can be accomplished with a force of 110 lbs. or less,typically about 100 lbs. (The demolding force would typically be applieddirectly to the gridwork of the preform 35, 110.)

The optional preform skid skirt at the opposite end of the element, canbe applied either before or after molding. In general, if a center plugis used within the media, it would be preformed before the describedmolding process. However, in some instances a center plug can be moldedat the same time as the overmold. This latter would require ensuringthat a part of the mold or some other configuration is provided, forappropriate dispensing of the urethane to accomplish this.

It is noted that in some instances, as described above, the preform 230could be attached to the media pack 231 by snap-fit arrangement.

In FIG. 16, the mold 180 is depicted with the media pack 231 and preform230 positioned therein, at molding. In this instance the media pack 231is depicted without the option skid skirt mounted therein.

V. The Optional Skid Skirt

In the discussion above with respect to FIG. 1, it was indicated thatthe skid skirt 30 was an optional component. This component is depictedin FIGS. 17 and 18.

Referring first to FIG. 17, a top plan view, the skid skirt 30 isdepicted. In FIG. 18, the skid skirt 30 is depicted in cross-sectionalview. Referring to FIG. 18, receiving area 30 a for the media pack, canbe viewed, along with outside surface 30 b configured to engagecomponentry in a housing, during installation, as desired. From theprinciples described in FIGS. 17 and 18, an analogous, but circular,component can be understood, if desired, for application in a circulararrangement. The skid skirt 30 is typically formed from a glass filled(for example 33% glass filled) nylon, secured in position with anadhesive.

VI. The Curable Seal Resin

Preferably with such arrangements, the polyurethane formulation chosenprovides for a high foam, very soft, molded end cap. In general, theprincipal issue is to utilize a formulation that provides for an end capthat is such that a robust seal will result under conditions which willallow for hand assembly and disassembly. This generally means that theseal range which has material is a relatively low density, and exhibitsappropriate and desirable compression load deflection and compressionset.

Although alternatives are possible, preferably the formula chosen willbe such as to provide end caps having an as molded density of no greaterthan 28 lbs./cubic foot (0.45 g/cu. cm.), more preferably no more than22 lbs./cubic foot (0.35 g/cu. cm.), typically no greater than 18lbs/cubic foot (0.29 g/cu. cm.) and preferably within the range of 12 to17 lbs/cubic foot (0.19-0.27 g/cu. cm.).

Herein the term “as molded density” is meant to refer to its normaldefinition of weight divided by volume. A water displacement test orsimilar test can be utilized to determine volume of a sample of themolded foam. It is not necessary when applying the volume test, topursue water absorption into the pores of the porous material, and todisplace the air the pores represent. Thus, the water volumedisplacement test used, to determine sample volume, would be animmediate displacement, without waiting for a long period to displaceair within the material pores. Alternately stated, only the volumerepresented by the outer perimeter of the sample need be used for the asmolded density calculation.

In general, compression load deflection is a physical characteristicthat indicates firmness, i.e. resistance to compression. In general, itis measured in terms of the amount of pressure required to deflect agiven sample of 25% of its thickness. Compression load deflection testscan be conducted in accord with ASTM 3574, incorporated herein byreference. In general, compression load deflection may be evaluated inconnection with aged samples. A typical technique is to measure thecompression load deflection on samples that have been fully cured for 72hours at 75° F. (24° C.) or forced cured at 190° F. (88° C.) for 5hours.

Preferred materials will be ones which when molded, show a compressionload deflection, in accord with ASTM 3574, on a sample measured afterheat aging at 158° F. (70° C.) for seven days, on average, of 14 psi(0.96 bar) or less, typically within the range of 6-14 psi (0.41-0.96bar), and preferably within the range of 7-10 psi (0.48-0.69 bar).

Compression set is an evaluation of the extent to which a sample of thematerial (that is subjected to compression of the defined type and underdefined conditions), returns to its previous thickness or height whenthe compression forces are removed. Conditions for evaluatingcompression set on urethane materials are also provided in ASTM 3574.

Typical desirable materials will be ones which, upon cure, provide amaterial that has a compression set of no more than about 18%, andtypically about 8-13%, when measured on a sample compressed to 50% ofits height and held at that compression at a temperature of 180° F. (82°C.) for 22 hours.

In general, the compression load deflection and compression setcharacteristics can be measured on sample plugs prepared from the sameresin as used to form the end cap, or on sample cut from the end cap.Typically, industrial processing methods will involve regularly makingtest sample plugs made from the resin material, rather than directtesting on portions cut from molded end caps.

Urethane resin systems useable to provide materials having physicalproperties within the as molded density, compression set and compressionload deflection definition as provided above, can be readily obtainedfrom a variety of polyurethane resin formulators, including suchsuppliers as BASF Corp., Wyandotte Mich., 48192.

In general, with any given industrial process to select the appropriatephysical characteristics with respect to the material, the key issuewill be management of the desired characteristics and the final product,with respect to mounting and dismounting of the element, as well asmaintenance of the seal over a variety of conditions. The physicalcharacteristics provided above are useable, but are not specificallylimiting with respect to products that may be considered viable. Inaddition, various element manufacturers, depending on the circumstances,may desire still further specifications, for example, cold temperaturecompression deflection, typically measured on the sample cooled to −40°F. (−40° C.), with the specification being for the pressure required tocause the compression under the ASTM test, for example, being 100 psi(6.9 bar) max.

One example usable material includes the following polyurethane,processed to an end product having an “as molded” density of 14-22pounds per cubic foot (0.22 g/cu. cm.-0.35 g/cu. cm.). The polyurethanecomprises a material made with 136070R resin and 13050U isocyanate,which are sold exclusively to the assignee Donaldson by BASFCorporation, Wyandotte, Mich. 48192.

The materials would typically be mixed in a mix ratio of 100 parts136070R resin to 45.5 parts 13050U isocyanate (by weight). The specificgravity of the resin is 1.04 (8.7 lbs/gallon) and for the isocyanate itis 1.20 (10 lbs/gallon). The materials are typically mixed with a highdynamic shear mixer. The component temperatures should be 70-95° F. Themold temperatures should be 115-135° F.

The resin material 136070R has the following description:

-   -   (a) Average molecular weight        -   1) Base polyether polyol=500-15,000        -   2) Diols=0-10,000        -   3) Triols=500-15,000    -   (b) Average functionality        -   1) total system=1.5-3.2    -   (c) Hydroxyl number        -   1) total systems=100-300    -   (d) Catalysts        -   1) amine=Air Products 0.1-3.0 PPH    -   (e) Surfactants        -   1) total system=0.1-2.0 PPH    -   (f) Water        -   1) total system=0.2-0.5%    -   (g) Pigments/dyes        -   1) total system=1-5% carbon black    -   (h) Blowing agent        -   1) water.

The 13050U isocyanate description is as follows:

-   -   (a) NCO content—22.4-23.4 wt %    -   (b) Viscosity, cps at 25° C.=600-800    -   (c) Density=1.21 g/cm³ at 25° C.    -   (d) Initial boiling pt.—190° C. at 5 mm Hg    -   (e) Vapor pressure=0.0002 Hg at 25° C.    -   (f) Appearance—colorless liquid    -   (g) Flash point (Densky-Martins closed cup)=200° C.

In more general terms, the portion of the resin that forms in thehousing seal, should typically be a material that cures to a density ofat least 10 lbs./cubic foot (0.16 grams/cc) would be preferred, althoughmaterials as low as 5 lbs./cubic foot (0.08 grams/cc) may be acceptablefor some light duty applications. Again it would be preferred that thematerial be one which cures to a density of no greater than about 22lbs./cubic foot (0.35 grams/cc), as discussed above, and preferably lessthan this value.

VII. Z-Filter Media Generally

Herein above it was discussed in general the media packs usable in thearrangements described, for example as media packs 2, 102, comprisez-filter media packs. It was indicated that a variety of alternate fluteshapes and seal types can be used in such media packs.

A. Z-Filter Media Configurations, Generally.

Fluted filter media can be used to provide fluid filter constructions ina variety of manners. One well known manner is as a z-filterconstruction. The term “z-filter construction” as used herein, is meantto refer to a filter construction in which individual ones ofcorrugated, folded or otherwise formed filter flutes are used to definesets of longitudinal, typically parallel, inlet and outlet filter flutesfor fluid flow through the media; the fluid flowing along the length ofthe flutes between opposite inlet and outlet flow ends (or flow faces)of the media. Some examples of z-filter media are provided in U.S. Pat.Nos. 5,820,646; 5,772,883; 5,902,364; 5,792,247; 5,895,574; 6,210,469;6,190,432; 6,350,296; 6,179,890; 6,235,195; Des. 399,944; Des. 428,128;Des. 396,098; Des. 398,046; and, Des. 437,401; each of these fifteencited references being incorporated herein by reference.

One type of z-filter media, utilizes two specific media componentsjoined together, to form the media construction. The two components are:(1) a fluted (typically corrugated) media sheet; and, (2) a facing mediasheet. The facing media sheet is typically non-corrugated, however itcan be corrugated, for example perpendicularly to the flute direction asdescribed in U.S. provisional 60/543,804, filed Feb. 11, 2004,incorporated herein by reference.

The fluted (typically corrugated) media sheet and the facing media sheettogether, are used to define media having parallel inlet and outletflutes. In some instances, the fluted sheet and facing sheet are securedtogether and are then coiled to form a z-filter media construction. Sucharrangements are described, for example, in U.S. Pat. Nos. 6,235,195 and6,179,890, each of which is incorporated herein by reference. In certainother arrangements, some non-coiled sections of fluted media secured tofacing media, are stacked on one another, to create a filterconstruction. An example of this is described in FIG. 11 of U.S. Pat.No. 5,820,646, incorporated herein by reference.

For specific applications as described herein, coiled arrangements arepreferred. Typically, coiling of the fluted sheet/facing sheetcombination around itself, to create a coiled media pack, is conductedwith the facing sheet directed outwardly. Some techniques for coilingare described in U.S. provisional application 60/467,521, filed May 2,2003 and PCT Application US 04/07927, filed Mar. 17, 2004, each of whichis incorporated herein by reference. The resulting coiled arrangementgenerally has, as the outer surface of the media pack, a portion of thefacing sheet.

The term “corrugated” used herein to refer to structure in media, ismeant to refer to a flute structure resulting from passing the mediabetween two corrugation rollers, i.e., into a nip or bite between tworollers, each of which has surface features appropriate to cause acorrugation affect in the resulting media. The term “corrugation” is notmeant to refer to flutes that are formed by techniques not involvingpassage of media into a bite between corrugation rollers. However, theterm “corrugated” is meant to apply even if the media is furthermodified or deformed after corrugation, for example by the foldingtechniques described in PCT WO 04/007054, published Jan. 22, 2004,incorporated herein by reference.

Corrugated media is a specific form of fluted media. Fluted media ismedia which has individual flutes (for example formed by such techniquesas corrugating or folding) extending thereacross.

Serviceable filter element or filter cartridge configurations utilizingz-filter media are sometimes referred to as “straight through flowconfigurations” or by variants thereof. In general, in this context whatis meant is that the serviceable filter elements generally have an inletflow end (or face) and an opposite exit flow end (or face), with flowentering and exiting the filter cartridge in generally the same straightthrough direction. The media pack is closed to passage therethrough ofunfiltered air. The term “serviceable” in this context is meant to referto a media containing filter cartridge that is periodically removed andreplaced from a corresponding fluid cleaner. In some instances, each ofthe inlet flow end and outlet flow end will be generally flat or planar,with the two parallel to one another. However, variations from this, forexample non-planar faces are possible.

A straight through flow configuration (especially for a coiled mediapack) is, for example, in contrast to serviceable filter cartridges suchas cylindrical pleated filter cartridges of the type shown in U.S. Pat.No. 6,039,778, incorporated herein by reference, in which the flowgenerally makes a turn as its passes through the serviceable cartridge.That is, in a U.S. Pat. No. 6,039,778 filter, the flow enters thecylindrical filter cartridge through a cylindrical side, and then turnsto exit through an end face (in forward-flow systems). In a typicalreverse-flow system, the flow enters the serviceable cylindricalcartridge through an end face and then turns to exit through a side ofthe cylindrical filter cartridge. An example of such a reverse-flowsystem is shown in U.S. Pat. No. 5,613,992, incorporated by referenceherein.

The term “z-filter media construction” and variants thereof as usedherein, without more, is meant to refer to any or all of: a web ofcorrugated or otherwise fluted media secured to facing media withappropriate sealing to allow for definition of inlet and outlet flutes;or, such a media coiled or otherwise constructed or formed into a threedimensional network of inlet and outlet flutes; and/or, a filterconstruction including such media.

In FIG. 19, an example of media 401 useable in z-filter media is shown.The media 401 is formed from a corrugated (fluted) sheet 403 and afacing sheet 404.

In general, the corrugated sheet 403, FIG. 19, is of a type generallycharacterized herein as having a regular, curved, wave pattern of flutesor corrugations 407. The term “wave pattern” in this context, is meantto refer to a flute or corrugated pattern of alternating troughs 407 band ridges 407 a. The term “regular” in this context is meant to referto the fact that the pairs of troughs and ridges (407 b, 407 a)alternate with generally the same repeating corrugation (or flute) shapeand size. (Also, typically in a regular configuration each trough 407 bis substantially an inverse of each ridge 407 a.) The term “regular” isthus meant to indicate that the corrugation (or flute) pattern comprisestroughs and ridges with each pair (comprising an adjacent trough andridge) repeating, without substantial modification in size and shape ofthe corrugations along at least 70% of the length of the flutes. Theterm “substantial” in this context, refers to a modification resultingfrom a change in the process or form used to create the corrugated orfluted sheet, as opposed to minor variations from the fact that themedia sheet 403 is flexible. With respect to the characterization of arepeating pattern, it is not meant that in any given filterconstruction, an equal number of ridges and troughs is necessarilypresent. The media 401 could be terminated, for example, between a paircomprising a ridge and a trough, or partially along a pair comprising aridge and a trough. (For example, in FIG. 19 the media 401 depicted infragmentary has eight complete ridges 407 a and seven complete troughs407 b.) Also, the opposite flute ends (ends of the troughs and ridges)may vary from one another. Such variations in ends are disregarded inthese definitions, unless specifically stated. That is, variations inthe ends of flutes are intended to be covered by the above definitions.

In the context of the characterization of a “curved” wave pattern ofcorrugations, the term “curved” is meant to refer to a corrugationpattern that is not the result of a folded or creased shape provided tothe media, but rather the apex 407 a of each ridge and the bottom 407 bof each trough is formed along a radiused curve. Although alternativesare possible, a typical radius for such z-filter media would be at least0.25 mm and typically would be not more than 3 mm. (Media that is notcurved, by the above definition, can also be useable.)

An additional characteristic of the particular regular, curved, wavepattern depicted in FIG. 19, for the corrugated sheet 403, is that atapproximately a midpoint 430 between each trough and each adjacentridge, along most of the length of the flutes 407, is located atransition region where the curvature inverts. For example, viewing backside or face 403 a, FIG. 19, trough 407 b is a concave region, and ridge407 a is a convex region. Of course when viewed toward front side orface 403 b, trough 407 b of side 403 a forms a ridge; and, ridge 407 aof face 403 a, forms a trough. (In some instances, region 430 can be astraight segment, instead of a point, with curvature inverting at endsof the straight segment 430.)

A characteristic of the particular regular, curved, wave patterncorrugated sheet 403 shown in FIG. 19, is that the individualcorrugations are generally straight. By “straight” in this context, itis meant that through at least 70% (typically at least 80%) of thelength between edges 408 and 409, the ridges 407 a and troughs 407 b donot change substantially in cross-section. The term “straight” inreference to corrugation pattern shown in FIG. 19, in part distinguishesthe pattern from the tapered flutes of corrugated media described inFIG. 1 of WO 97/40918 and PCT Publication WO 03/47722, published Jun.12, 2003, incorporated herein by reference. The tapered flutes of FIG. 1of WO 97/40918, for example, would be a curved wave pattern, but not a“regular” pattern, or a pattern of straight flutes, as the terms areused herein.

Referring to the present FIG. 19 and as referenced above, the media 401has first and second opposite edges 408 and 409. When the media 401 iscoiled and formed into a media pack, in general edge 409 will form aninlet end for the media pack and edge 408 an outlet end, although anopposite orientation is possible.

Adjacent edge 408 the sheets 403, 404 are sealed to one another, forexample by sealant, in this instance in the form of a sealant bead 410,sealing the corrugated (fluted) sheet 403 and the facing sheet 404together. Bead 410 will sometimes be referred to as a “single facer”bead, when it is applied as a bead between the corrugated sheet 403 andfacing sheet 404, to form the single facer or media strip 401. Sealantbead 410 seals closed individual flutes 411 adjacent edge 408, topassage of air therefrom.

Adjacent edge 409, is provided sealant, in this instance in the form ofa seal bead 414. Seal bead 414 generally closes flutes 415 to passage ofunfiltered fluid therein, adjacent edge 409. Bead 414 would typically beapplied as the media 401 is coiled about itself, with the corrugatedsheet 403 directed to the inside. Thus, bead 414 will form a sealbetween a back side 417 of facing sheet 404, and side 418 of thecorrugated sheet 403. The bead 414 will sometimes be referred to as a“winding bead” when it is applied as the strip 401 is coiled into acoiled media pack. If the media 401 were cut in strips and stacked,instead of coiled, bead 414 would be a “stacking bead.”

In some applications, the corrugated sheet 403 is also tacked to thefacing sheet 4 at various points along the flute length, as shown atlines 404 a.

Referring to FIG. 19, once the media 401 is incorporated into a mediapack, for example by coiling or stacking, it can be operated as follows.First, air in the direction of arrows 412, would enter open flutes 411adjacent end 409. Due to the closure at end 408, by bead 410, the airwould pass through the media shown by arrows 413. It could then exit themedia pack, by passage through open ends 415 a of the flutes 415,adjacent end 408 of the media pack. Of course operation could beconducted with air flow in the opposite direction, as discussed forexample with respect to FIG. 24. The point being that in typical airfilter applications, at one end or face of the media pack unfiltered airflow goes in, and at an opposite end or face the filtered air flow goesout, with no unfiltered air flow through the pack or between the faces.

For the particular arrangement shown herein in FIG. 19, the parallelcorrugations 7 a, 7 b are generally straight completely across themedia, from edge 708 to edge 709. Straight flutes or corrugations can bedeformed or folded at selected locations, especially at ends.Modifications at flute ends for closure are generally disregarded in theabove definitions of “regular,” “curved” and “wave pattern.”

Z-filter constructions which do not utilize straight, regular curvedwave pattern corrugation (flute) shapes are known. For example in Yamadaet al. U.S. Pat. No. 5,562,825 corrugation patterns which utilizesomewhat semicircular (in cross section) inlet flutes adjacent narrowV-shaped (with curved sides) exit flutes are shown (see FIGS. 1 and 3,of U.S. Pat. No. 5,562,825). In Matsumoto, et al. U.S. Pat. No.5,049,326 circular (in cross-section) or tubular flutes defined by onesheet having half tubes attached to another sheet having half tubes,with flat regions between the resulting parallel, straight, flutes areshown, see FIG. 2 of Matsumoto '326. In Ishii, et al. U.S. Pat. No.4,925,561 (FIG. 1) flutes folded to have a rectangular cross section areshown, in which the flutes taper along their lengths. In WO 97/40918(FIG. 1), flutes or parallel corrugations which have a curved, wavepatterns (from adjacent curved convex and concave troughs) but whichtaper along their lengths (and thus are not straight) are shown. Also,in WO 97/40918 flutes which have curved wave patterns, but withdifferent sized ridges and troughs, are shown.

In general, the filter media is a relatively flexible material,typically a non-woven fibrous material (of cellulose fibers, syntheticfibers or both) often including a resin therein, sometimes treated withadditional materials. Thus, it can be conformed or configured into thevarious corrugated patterns, without unacceptable media damage. Also, itcan be readily coiled or otherwise configured for use, again withoutunacceptable media damage. Of course, it must be of a nature such thatit will maintain the required corrugated configuration, during use.

In the corrugation process, an inelastic deformation is caused to themedia. This prevents the media from returning to its original shape.However, once the tension is released the flute or corrugations willtend to spring back, recovering only a portion of the stretch andbending that has occurred. The facing sheet is sometimes tacked to thefluted sheet, to inhibit this spring back in the corrugated sheet.

Also, typically, the media contains a resin. During the corrugationprocess, the media can be heated to above the glass transition point ofthe resin. When the resin then cools, it will help to maintain thefluted shapes.

The media of the corrugated sheet 403, facing sheet 404 or both, can beprovided with a fine fiber material on one or both sides thereof, forexample in accord with U.S. Pat. No. 6,673,136, incorporated herein byreference.

An issue with respect to z-filter constructions relates to closing ofthe individual flute ends. Typically a sealant or adhesive is provided,to accomplish the closure. As is apparent from the discussion above, intypical z-filter media, especially that which uses straight flutes asopposed to tapered flutes, large sealant surface areas (and volume) atboth the upstream end and the downstream end are needed. High qualityseals at these locations are critical to proper operation of the mediastructure that results. The high sealant volume and area, creates issueswith respect to this.

Attention is now directed to FIG. 20, in which a z-filter mediaconstruction 440 utilizing a regular, curved, wave pattern corrugatedsheet 443, and a facing (in this instance non-corrugated) sheet 444, isdepicted. The distance D1, between points 450 and 451, defines theextension of facing media 444 in region 452 underneath a givencorrugated flute 453. The length D2 of the arcuate media for thecorrugated flute 453, over the same distance D1 is of course larger thanD1, due to the shape of the corrugated flute 453. For a typical regularshaped media used in fluted filter applications, the linear length D2 ofthe media 453 between points 450 and 451 will generally be at least 1.2times D1. Typically, D2 would be within a range of 1.2-2.0 time D1,inclusive. One particularly convenient arrangement for air filters has aconfiguration in which D2 is about 1.25-1.35×D1. Such media has, forexample, been used commercially in Donaldson Powercore™ Z-filterarrangements. Herein the ratio D2/D1 will sometimes be characterized asthe flute/flat ratio or media draw for the corrugated (fluted) media.

In the corrugated cardboard industry, various standard flutes have beendefined. For example the standard E flute, standard X flute, standard Bflute, standard C flute and standard A flute. FIG. 21, attached, incombination with Table A below provides definitions of these flutes.

Donaldson Company, Inc., (DCI) the assignee of the present disclosure,has used variations of the standard A and standard B flutes, in avariety of z-filter arrangements. These flutes are also defined in TableA and FIG. 21. TABLE A (Flute definitions for FIG. 3) DCI A Flute:Flute/flat = 1.52:1; The Radii (R) are as follows: R1000 = .0675 inch(1.715 mm); R1001 = .0581 inch (1.476 mm); R1002 = .0575 inch (1.461mm); R1003 = .0681 inch (1.730 mm); DCI B Flute: Flute/flat = 1.32:1;The Radii (R) are as follows: R1004 = .0600 inch (1.524 mm); R1005 =.0520 inch (1.321 mm); R1006 = .0500 inch (1.270 mm); R1007 = .0620 inch(1.575 mm); Std. E Flute: Flute/flat = 1.24:1; The Radii (R) are asfollows: R1008 = .0200 inch (.508 mm); R1009 = .0300 inch (.762 mm);R1010 = .0100 inch (.254 mm); R1011 = .0400 inch (1.016 mm); Std. XFlute: Flute/flat = 1.29:1; The Radii (R) are as follows: R1012 = .0250inch (.635 mm); R1013 = .0150 inch (.381 mm); Std. B Flute: Flute/flat =1.29:1; The Radii (R) are as follows: R1014 = .0410 inch (1.041 mm);R1015 = .0310 inch (.7874 mm); R1016 = .0310 inch (.7874 mm); Std. CFlute: Flute/flat = 1.46:1; The Radii (R) are as follows: R1017 = .0720inch (1.829 mm); R1018 = .0620 inch (1.575 mm); Std. A Flute: Flute/flat= 1.53:1; The Radii (R) are as follows: R1019 = .0720 inch (1.829 mm);R1020 = .0620 inch (1.575 mm).

Of course other, standard, flutes definitions from the corrugated boxindustry are known.

In general, standard flute configurations from the corrugated boxindustry can be used to define corrugation shapes or approximatecorrugation shapes for corrugated media. Comparisons above between theDCI A flute and DCI B flute, and the corrugation industry standard A andstandard B flutes, indicate some convenient variations.

B. Manufacture of Coiled Media Configurations Using Fluted Media,Generally.

In FIG. 22, one example of a manufacturing process for making a mediastrip corresponding to strip 401, FIG. 19 is shown. In general, facingsheet 464 and the fluted (corrugated) sheet 466 having flutes 468 arebrought together to form a media web 469, with an adhesive bead locatedtherebetween at 470. The adhesive bead 470 will form a single facer bead410, FIG. 19. An optional darting process occurs at station 471 to formcenter darted section 472 located mid-web. The z-filter media or Z-mediastrip 474 can be cut or slit at 475 along the bead 470 to create twopieces 476, 477 of z-filter media 474, each of which has an edge with astrip of sealant (single facer bead) extending between the corrugatingand facing sheet. Of course, if the optional darting process is used,the edge with a strip of sealant (single facer bead) would also have aset of flutes darted at this location.

Also, if tack beads or other tack connections 404 a, FIG. 19, are used,they can be made, as the sheets 464, 466 are brought together.

Techniques for conducting a process as characterized with respect toFIG. 22 are described in PCT WO 04/007054, published Jan. 22, 2004incorporated herein by reference.

Still in reference to FIG. 22, before the z-filter media 474 is putthrough the darting station 471 and eventually slit at 475, it must beformed. In the schematic shown in FIG. 22, this is done by passing asheet of media 492 through a pair of corrugation rollers 494, 495. Inthe schematic shown in FIG. 22, the sheet of media 492 is unrolled froma roll 496, wound around tension rollers 498, and then passed through anip or bite 502 between the corrugation rollers 494, 495. Thecorrugation rollers 494, 495 have teeth 504 that will give the generaldesired shape of the corrugations after the flat sheet 492 passesthrough the nip 502. After passing through the nip 502, the sheet 492becomes corrugated across the machine direction and is referenced at 466as the corrugated sheet. The corrugated sheet 466 is then secured tofacing sheet 464. (The corrugation process may involve heating themedia, in some instances.)

Still in reference to FIG. 22, the process also shows the facing sheet464 being routed to the darting process station 471. The facing sheet464 is depicted as being stored on a roll 506 and then directed to thecorrugated sheet 466 to form the Z-media 474. The corrugated sheet 466and the facing sheet 464 are secured together by adhesive or by othermeans (for example by sonic welding).

Referring to FIG. 22, an adhesive line 470 is shown used to securecorrugated sheet 466 and facing sheet 464 together, as the sealant bead.Alternatively, the sealant bead for forming the facing bead could beapplied as shown as 470 a. If the sealant is applied at 470 a, it may bedesirable to put a gap in the corrugation roller 495, and possibly inboth corrugation rollers 494, 495, to accommodate the bead 470 a.

The type of corrugation provided to the corrugated media is a matter ofchoice, and will be dictated by the corrugation or corrugation teeth ofthe corrugation rollers 494, 495. One preferred corrugation pattern willbe a regular curved wave pattern corrugation of straight flutes, asdefined herein above. A typical regular curved wave pattern used, wouldbe one in which the distance D2, as defined above, in a corrugatedpattern is at least 1.2 times the distance D1 as defined above. In onepreferred application, typically D2=1.25−1.35×D1. In some instances thetechniques may be applied with curved wave patterns that are not“regular,” including, for example, ones that do not use straight flutes.

As described, the process shown in FIG. 22 can be used to create thecenter darted section 472. FIG. 23 shows, in cross-section, one of theflutes 468 after darting and slitting.

A fold arrangement 518 can be seen to form a darted flute 520 with fourcreases 521 a, 521 b, 521 c, 521 d. The fold arrangement 518 includes aflat first layer or portion 522 that is secured to the facing sheet 464.A second layer or portion 524 is shown pressed against the first layeror portion 522. The second layer or portion 524 is preferably formedfrom folding opposite outer ends 526, 527 of the first layer or portion522.

Still referring to FIG. 23, two of the folds or creases 521 a, 521 bwill generally be referred to herein as “upper, inwardly directed” foldsor creases. The term “upper” in this context is meant to indicate thatthe creases lie on an upper portion of the entire fold 520, when thefold 520 is viewed in the orientation of FIG. 23. The term “inwardlydirected” is meant to refer to the fact that the fold line or creaseline of each crease 521 a, 521 b, is directed toward the other.

In FIG. 23, creases 521 c, 521 d, will generally be referred to hereinas “lower, outwardly directed” creases. The term “lower” in this contextrefers to the fact that the creases 521 c, 521 d are not located on thetop as are creases 521 a, 521 b, in the orientation of FIG. 23. The term“outwardly directed” is meant to indicate that the fold lines of thecreases 521 c, 521 d are directed away from one another.

The terms “upper” and “lower” as used in this context are meantspecifically to refer to the fold 520, when viewed from the orientationof FIG. 23. That is, they are not meant to be otherwise indicative ofdirection when the fold 520 is oriented in an actual product for use.

Based upon these characterizations and review of FIG. 23, it can be seenthat a preferred regular fold arrangement 518 according to FIG. 23 inthis disclosure is one which includes at least two “upper, inwardlydirected, creases.” These inwardly directed creases are unique and helpprovide an overall arrangement in which the folding does not cause asignificant encroachment on adjacent flutes.

A third layer or portion 528 can also be seen pressed against the secondlayer or portion 524. The third layer or portion 528 is formed byfolding from opposite inner ends 530, 531 of the third layer 528.

Another way of viewing the fold arrangement 518 is in reference to thegeometry of alternating ridges and troughs of the corrugated sheet 566.The first layer or portion 522 is formed from an inverted ridge. Thesecond layer or portion 524 corresponds to a double peak (afterinverting the ridge) that is folded toward, and in preferredarrangements folded against, the inverted ridge.

Techniques for providing the optional dart described in connection withFIG. 23, in a preferred manner, are described in PCT WO 04/007054,incorporated herein by reference. Techniques for coiling the media, withapplication of the winding bead, are described in PCT application US04/07927, filed Mar. 17, 2004 and incorporated herein by reference.

Techniques described herein are particularly well adapted for use withmedia packs that result from coiling a single sheet comprising acorrugated sheet/facing sheet combination, i.e., a “single facer” strip.Certain of the techniques can be applied with arrangements that, insteadof being formed by coiling, are formed from a plurality of strips ofsingle facer.

Coiled media pack arrangements can be provided with a variety ofperipheral perimeter definitions. In this context the term “peripheral,perimeter definition” and variants thereof, is meant to refer to theoutside perimeter shape defined, looking at either the inlet end or theoutlet end of the media pack. Typical shapes are circular as describedin PCT WO 04/007054 and PCT application US 04/07927. Other useableshapes are obround, some examples of obround being oval shape. Ingeneral oval shapes have opposite curved ends attached by a pair ofopposite sides. In some oval shapes, the opposite sides are also curved.In other oval shapes, sometimes called racetrack shapes, the oppositesides are generally straight. Racetrack shapes are described for examplein PCT WO 04/007054 and PCT application US 04/07927.

Another way of describing the peripheral or perimeter shape is bydefining the perimeter resulting from taking a cross-section through themedia pack in a direction orthogonal to the winding axis of the coil.

Opposite flow ends or flow faces of the media pack can be provided witha variety of different definitions. In many arrangements, the ends aregenerally flat and perpendicular to one another. In other arrangements,the end faces include tapered, coiled, stepped portions which can eitherbe defined to project axially outwardly from an axial end of the sidewall of the media pack; or, to project axially inwardly from an end ofthe side wall of the media pack. Examples of such media packarrangements are shown in U.S. Provisional Application 60/578,482, filedJun. 8, 2004, incorporated herein by reference.

The flute seals (for example from the single facer bead, winding bead orstacking bead) can be formed from a variety of materials. In variousones of the cited and incorporated references, hot melt or polyurethaneseals are described as possible for various applications. Such materialsare also useable for arrangements as characterized herein.

When the media is coiled, generally a center of the coil needs to beclosed, to prevent passage of unfiltered air between the flow faces;i.e., through the media pack. Some approaches to this are referencedbelow. Others are described in U.S. Provisional 60/578,482, filed Jun.8, 2004; and U.S. Provisional 60/591,280, filed Jul. 26, 2004.

The media chosen for the corrugated sheet and facing sheet can be thesame or different. Cellulose fiber, synthetic fiber or mixed media fibermaterials can be chosen. The media can be provided with a fine fiberlayer applied to one or more surface, for example in accord with U.S.Pat. No. 6,673,136, issued Jan. 6, 2004, the complete disclosure ofwhich is incorporated herein by reference. When such material is used ononly one side of each sheet, it is typically applied on the side(s)which will form the upstream side of inlet flutes.

Above it was discussed that flow could be opposite to the directionshown in FIG. 19.

In FIG. 24, a schematic depiction of media useable in such z-filtermedia packs as shown. The schematic depiction of FIG. 24 is generic, andis not meant to indicate unique or preferred seal type or flute shapes.

Referring to FIG. 24, the reference numeral 300 generally indicates asingle facer comprising corrugated sheet 301 secured to flat sheet 302.It is noted that the flat sheet 302 does not have to be perfectly flat,it may comprise a sheet that itself has very small corrugations andother formations therein.

Particular single facer 300 depicted, could be coiled around itself oraround a core and then around itself, typically with flat sheet 302 tothe outside. For the arrangement shown, edge 310 will form the inletface in the eventual media pack and end or edge 311 will form the outletflow faces. Thus arrows 312 represent inlet arrows and arrows 313represent outlet flow arrows. Sheet 315 is merely meant to schematicallyrepresent a flat sheet corresponding to sheet 302, of the next wind.

Adjacent edge 311 is provided a single facer seal arrangement 320. Inthis instance the single facer shield arrangement 320 comprises a beadof sealant 321 between corrugated sheet 301 and flat sheet 302,positioned along edge 310 or within about 10% of the total length of theflutes, i.e., the distance between inlet edge 310 and outlet edge 311. Avariety of materials and arrangements can be used for the sealarrangement 320. The seal arrangement could comprise a corrugated orfolded arrangement, sealed with a sealant, or sealed by other means. Theparticular seal arrangement 320 depicted, could comprise a bead of hotmelt sealant, although alternatives are possible. The seals at 320 couldbe darted or folded, as shown for FIGS. 4 and 10.

Adjacent end 310 a winding seal 330 is depicted. Winding seal 330generally provides for a seal between layers adjacent edge 311, as thesingle facer 300 is coiled. Preferably winding seal 330 is positionedwithin 10% of the total length of the flutes (i.e., the distance betweenedge 311 and 310) of edge 310.

If is the very ends (lead and tail) of the single facer need to besealed between the corrugated and flat sheets, sealant can be applied atthese locations to do so.

VIII. General Background Regarding Air Cleaner Systems

The principles and arrangements described herein are useable in avariety of systems. One particular system is depicted schematically inFIG. 25, generally at 650. In FIG. 25, equipment 652, such as a vehicle652 a having an engine 653 with some defined rated air flow demand, forexample in the range of 50 cfm to 2000 cfm (cubic feet per minute)(i.e., 1.4-57 cubic meters/minute) is shown schematically. Althoughalternatives are possible, the equipment 652 may, for example, comprisea bus, an over-the-highway truck, an off-road vehicle, a tractor, alight-duty or medium-duty truck, or a marine vehicle such as a powerboat. The engine 653 powers the equipment 652 upon fuel combustion. InFIG. 25, air flow is shown drawn into the engine 653 at an air intake atregion 655. An optional turbo 656 is shown in phantom, as optionallyboosting the air intake to the engine 653. The turbo 656 is showndownstream from an air cleaner 660, although alternate arrangement arepossible.

The air cleaner 660 has a filter cartridge 662 and is shown in the airinlet stream to the engine 653. In general, in operation, air is drawnin at arrow 664 into the air cleaner 660 and through the filtercartridge 662. Upon passage through the air cleaner 660, selectedparticles and contaminants are removed from the air. The cleaned airthen flows downstream at arrow 666 into the intake 655. From there, theair flow is directed into the engine 653.

In a typical air cleaner 660, the filter cartridge 662 is a serviceablecomponent. That is, the cartridge 662 is removable and replaceablewithin the air cleaner 660. This allows the cartridge 662 to beserviced, by removal and replacement, with respect to remainder of aircleaner 660, when the cartridge 662 becomes sufficiently loaded withdust or other contaminant, to require servicing.

IX. One Type of Useable Central Core for Round Coiled Media Packs

Above it was discussed, in connection with the discussion of FIG. 9, thecore 113 could be filled with a plug. An example is described below, andshown in FIG. 26. In FIG. 26, a fragmentary portion of media pack 102,FIG. 9, is shown. Referring to FIG. 26, the coiled media pack 102includes center core 113. The core 113 needs to be sealed againstunfiltered air flow therethrough. This is done by center piece, plug orcore 721. Core 721 also provides for a lead end seal of the single facerstrip which is coiled to form the media pack 102.

More specifically, the media lead end is shown in phantom at 722. Forthe arrangement shown, between regions 724 and 725, the mold-in-placeplug 721 is provided in center 113. Thus, it seals at least a portion ofthe lead end 724 of the media strip.

Still referring to FIG. 26, in general the preferred plug 721 is apoured and cured core. By this it is meant that the plug 721 resultsfrom pouring a fluid resin into center 113 and allowing the resin tocure. A variety of shapes and sizes for the plug 721 are possible.

Typically when used as a lead end seal, the plug 721 will be configuredto extend along, or engulf, at least 80% of the lead end seal length,typically at least 90% of that length. In some instances, for example inthe instance shown in FIG. 26, the plug 721 may be configured to coveror enclose the entire lead end 722.

The plug 721 can be configured with recesses as shown, or it can beconfigured to have no recesses or even to have one or more projectionsextending outwardly from the element.

When the plug 721 is provided with recesses as shown, typically region724 will be spaced from end face 105 at least 2 mm, and region 725 willbe spaced from end 105 a by at least 2 mm.

Region 727 extends from region 724 toward face 105, and terminates atface 105 as shown, or spaced therefrom within a preferred distance. Thisregion defines an outer seal wall 728 with a hollow center 729. The sealwall 728 continues the sealing of the lead end 722 of the media pack102. Region 727 can be viewed as a concave end to plug 721. Herein,region 727 will sometimes be referred to as a concave end with anaxially outwardly projecting end skirt 728.

Skirt 728 is not required to terminate at end face 105, although suchtermination is shown in the arrangement of FIG. 26. It can terminateshort thereof and can still accomplish much of its function of sealingthe lead end 722, for example, by terminating at or adjacent the windingbead seal or single facer seal in this region.

Analogously, between region 725 and surface 105 a, region 734 isprovided, with outer seal area 735 and inner center recess 736. The sealarea 735 provides, among other things, for sealing of the lead end 722of the media 102 between region 725 and surface 105 a. The seal area 735can be seen as a concave end to plug 721. Herein, region 725 willsometimes be referred to as a concave end with an axially outwardlyprojecting end skirt 735. In some instances end skirt 735 is notrequired to terminate adjacent end face 105 a, as shown. Rather skirt735 can terminate short of end face 105 a, and still accomplish anappropriate seal of the lead end 102 at this location, by terminatingadjacent or in cooperation with a winding bead or seal bead at thislocation.

Still referring to FIG. 26, although not shown, structure could beembedded within plug 721. For example, a hollow core or other structurefrom a winding process could be left within region 113, to be engulfedwithin core 721 as a result of a molding operation.

The plug 721 can be molded-in-place, from a resin port into core 113. Asan example, a plug could be provided projecting into core 113 from endface 105, having an appropriate shape. The resin could be poured inplace, and a second plug put in place projecting into core 113 from endface 105 a. A foamed urethane could be used in the resin for example,which would rise an form the shape shown. This molding operation couldbe conducted before the molding operation discussed above in connectionwith FIGS. 11-16. In the alternative, the mold arrangement 180 could beprovided with the appropriate plug projecting into the central core 113of the media pack involved, with the opposite end being formed by anappropriate plug.

With respect to the core, urethane having an as molded density of nomore than 15 lbs. per cubic foot (0.24 grams/cc), and sometimes no morethan 10 lbs. per cubic foot (0.16 grams/cc), can be used, althoughalternatives of higher density, can be used. It is anticipated that theas molded density would typically be at least 5 lbs./cubic foot (0.08grams/cc).

1. A filter element comprising: (a) a media pack including oppositeinlet and outlet ends; the media pack defining: (i) a set of inletflutes open at the inlet end of the media pack to passage of air to befiltered therein; the inlet flutes being closed at a location at or nearthe outlet end of the media pack; (ii) a set of outlet flutes closed topassage of air to be filtered therein at a location at or near the inletend of the media pack and open to passage of filtered air therefrom atthe outlet end of the media pack; and (iii) the media pack being closedto flow of unfiltered air into the inlet end and then outwardly from theopposite outlet end without filtering; (b) a preform positioned adjacenta first one end of the inlet and outlet ends of the media pack; (i) thepreform having a housing seal support section projecting outwardly froma first one of the inlet and outlet ends of the media pack; (c) anovermold formed of a sealing material having: (i) a first portionsealing an interface between the preform and the first end of the mediapack at which the preform is positioned; and, (ii) a second portionoriented to form an air cleaner seal having a radially directed sealportion providing a radial seal between the filter element and an aircleaner, in use; (iii) the first and second portions of the overmoldbeing integral with one another.
 2. A filter element according to claim1 wherein: (a) the media pack is a coiled pack having an outer sidewall;(b) no portion of the preform extends around the outer sidewall of themedia pack; and, (c) the overmold extends along the media pack sidewalla distance of at least mm from the first end of the media pack.
 3. Afilter element according to claim 2 wherein: (a) the overmold comprisesfoamed polyurethane.
 4. A filter element according to claim 3 wherein:(a) the preform is positioned adjacent the media pack outlet end.
 5. Afilter element according to claim 4 wherein: (a) the preform includesthe housing seal support portion and a radially outwardly directed skirtportion; (i) the housing seal support portion and the radially outwardlydirected skirt portion being integral with one another; and (ii) theradially outwardly projecting skirt portion having an outermost edgepositioned at the interface between the preform and the media pack.
 6. Afilter element according to claim 5 wherein: (a) the radially outwardlydirected skirt extends at an angle within the range of 20 to 70°, fromthe media pack.
 7. A filter element according to claim 6 wherein: (a)the preform includes a media face cross-piece arrangement integraltherewith.
 8. A filter element according to claim 7 wherein: (a) thepreform comprises a molded nylon piece.
 9. A filter element according toclaim 6 wherein: (a) the media pack has an oval shaped cross-section.10. A filter element according to claim 6 wherein: (a) the media packcomprises a racetrack shaped cross-section having two, opposite, curvedends and two, opposite, generally straight sides.
 11. A filter elementaccording to claim 6 wherein: (a) the media pack has a circularcross-section.
 12. A filter element according to claim 6 wherein: (a)the media pack has an outside tail end edge secured down by a strip ofsealant.
 13. A filter element according to claim 12 wherein: (a) thestrip of sealant terminates at a location spaced at least 4 mm from themedia pack outlet end; and, at a location underneath the overmold.
 14. Afilter element according to claim 6 wherein: (a) inlet flute ends,adjacent the outlet end of the media pack, are closed by a sealant bead.15. A filter element according to claim 14 wherein: (a) inlet fluteends, adjacent the outlet end of the media pack, are closed by a singlefacer sealant bead.
 16. A filter element according to claim 15 wherein:(a) inlet flute ends, adjacent the outlet end of the media pack, areclosed by media darts.
 17. A filter element according to claim 6wherein: (a) outlet flutes, adjacent the inlet end of the media pack,are closed by a winder bead of sealant.
 18. A filter element accordingto claim 6 wherein: (a) the media pack includes an outermost wrap ofsingle facer; and (b) a portion of foamed urethane, integral with aremainder of the overmold, is positioned closing outlet ends ofotherwise open outlet flutes, adjacent an outlet face and in theoutermost wrap of single facer.
 19. A filter element according to claim6 wherein: (a) the preform includes a rib thereon, directed toward anoutlet face of the media pack.
 20. A method of forming an elementaccording to any one of claims 1-19, the method including steps of: (a)positioning an uncured foaming urethane in a reservoir of a mold; (b)positioning a preform and an end of a media pack in the mold, with aportion of the mold pressed against an outside surface of the media packat a location spaced at least 5 mm from the end of the media pack in themold; and (c) allowing the uncured foaming urethane to rise and cure toform an overmold around the preform and covering an interface betweenthe media pack and the preform.
 21. A method according to claim 20including a step of: (a) allowing a portion of the urethane which formsthe overmold to rise into selected ones of otherwise outlet flutes ofthe media pack.
 22. An air cleaner comprising: (a) an air cleanerhousing; and (b) a serviceable filter element comprising: (i) a mediapack including opposite inlet and outlet ends; the media pack defining:(A) a set of inlet flutes open at the inlet end of the media pack topassage of air to be filtered therein; the inlet flutes being closed ata location at or near the outlet end of the media pack; (B) a set ofoutlet flutes closed to passage of air to be filtered therein at or nearthe inlet end of the media pack and open to passage of filtered airtherefrom at the outlet end of the media pack; and (C) the media packbeing closed to flow of unfiltered air into the inlet end and thenoutwardly from the opposite outlet end without filtering; (ii) a preformpositioned adjacent a first one end of the inlet and outlet ends of themedia pack; (A) the preform having a housing seal support sectionprojecting outwardly from a first one of the inlet and outlet ends ofthe media pack; (iii) an overmold formed of a sealing material having:(A) a first portion sealing an interface between the preform and thefirst end of the media pack at which the preform is positioned; and, (B)a second portion oriented to form an air cleaner seal having a radiallydirected seal portion providing a radial seal between the filter elementand an air cleaner, in use; (C) the first and second portions of theovermold being integral with one another. (c) the filter element beingremovably sealed to the air cleaner by a radial seal between the secondportion of the overmold and the air cleaner.